mesa/st: keep surface_copy arguments positive

The src/dest x,y, and w,h arguments of the pipe->surface_copy
function are unsigned and the drivers aren't expecting negative
(or extremly-large unsigned) values as inputs.  Trim the requests
at the state-tracker level before passing down.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index 98f109fc65..b182106fd5 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -1337,6 +1337,34 @@ st_copy_texsubimage(GLcontext *ctx,
       return;
    }
 
+   if (srcX < 0) {
+      width -= -srcX;
+      destX += -srcX;
+      srcX = 0;
+   }
+
+   if (srcY < 0) {
+      height -= -srcY;
+      destY += -srcY;
+      srcY = 0;
+   }
+
+   if (destX < 0) {
+      width -= -destX;
+      srcX += -destX;
+      destX = 0;
+   }
+
+   if (destY < 0) {
+      height -= -destY;
+      srcY += -destY;
+      destY = 0;
+   }
+
+   if (width < 0 || height < 0)
+      return;
+
+
    assert(strb);
    assert(strb->surface);
    assert(stImage->pt);